This invention relates generally to a supercapacitor and a method for making the same. More particularly, this invention relates to a supercapacitor desalination cell and a method for making the same.
Supercapacitors are commonly used as energy storage cells. Generally, the supercapacitors are of a double layer type, in which a pair of electrodes typically comprising particulate activated carbon are separated by a microporous, electron-insulating, ion-conducting separator element, comprising a uniformly-dispersed electrolyte component. The structure of the typical supercapacitor further comprises electrically conductive current collector elements in intimate contact with the respective electrodes.
Applying an electrical potential across the electrodes causes charges to build up in the double layer, which exists at the electrode/electrolyte interface. In the supercapacitor, internal resistance often exists between the electrodes and the separator element as well as inside the electrodes. Accordingly, when charging or discharging the supercapacitor, especially the supercapacitor desalination cell, a large amount of energy may be consumed in order to overcome the internal resistance to urge anions and cations in the electrolyte to move to the respective electrodes or disassociate from the electrodes into the electrolyte.
Attempts have been made to reduce the internal resistance in the supercapacitor through some manner of unifying the particulate carbon electrode composition and conductive collectors. A process of high temperature sintering of the elements to achieve this end is described in U.S. Pat. No. 5,115,378, yet, as is apparent there, the extensive processing steps and high-energy consumption lead to economic undesirability of this approach. Further limiting the general acceptance of the process is the intractability of the resulting solid and unyielding preformed capacitor body, which cannot be readily shaped to conform to special requirements of varying utilizing devices.
Therefore, there is a need for a new and improved supercapacitor structure and a method for making the same to reduce the internal resistance therein.